Why not? Often the reply of Barry Shepherd, the founder of Shepherd Thermoforming & Packaging, when asked – could this be done in thermoforming?
“Barry has demonstrated great dedication to the thermoforming industry over the years,” said Mark Strachan, SPE Thermoforming Division chairman, in a statement, “As a forward thinker and a visionary, Barry has a desire to further the industry and has generously and willingly shared his vast knowledge and experience with us.” – excerpt from Plastics News article.
Forward thinking meant nothing without acting and implementing. In the mid 90’s, Shepherd
won business with a large healthcare company to produce thermoformed blisters. These small blisters were automatically machine fed and sealed to a blister card so cut registration was critical. Many previous thermoforming companies had walked away from this business or over priced in order to control the flange dimensions. Barry set out to develop a method to locate the steel rule die over each cavity (commonly referred as a floating steel rule die) so that the flange was consistent on each part across the index thus, cut registration was precise.
Another instance of forward thinking was gravity activated undercuts. Thermoforming a part required draft angles around the part in order to lift the formed rigid plastic off of the mould. For a stack feature that does not require the traditional 180° stack. The undercuts that create the stack features are typically difficult to release from a mould during in-line thermoforming. This innovation allows the undercut on the mould to hinge away from the part as it releases from the mould. Once cleared of the part the strategic weighting and hinge point allow the undercut to fall back into place using only gravity.
Some of these methods were patentable but Barry’s unselfish philosophy was to share it with his friends at SPE and the thermoforming world to further the industry as a whole. As Barry would say, why not?